In an information processing system that sends and receives information via a network such as the Internet, an authentication operation is performed between communications partners using a private key that is registered in advance.
For example, regarding a signature method using a signature key that is updated based on a verification key and an application ID, in order to enable updating of the signature key in the units of sections such as applications and versions; a device is available that updates the application ID in the units of sections, generates difference information for the purpose of updating the signature key, and updates the signature key based on the updated application IDs and the difference information.
A private key that is used in an authentication operation is constantly subject to danger of being leaked or lost. In case the private key is leaked, it becomes necessary to reregister a new private key. In many cases, the leakage of the private key is attributed to the vulnerability of the system software (firmware) that controls the information processing terminal. In case the system software is likely to have been damaged due to tampering, regardless of whether a private key is reregistered, it is not possible to accept that the confidentiality has been completely recovered. For example, in a system in which a plurality of information processing terminals is connected to a server, in case the system software stored in an information processing terminal is tampered, it is likely that the identification information of that information processing terminal is also tampered. Hence, the server cannot entirely identify the information processing terminal for reregistering the private key. In such a case, a worker needs to visit the installation location of the concerned information processing terminal to deal with the issue. However, particularly if there are a number of information processing terminals, such a task becomes a huge burden in the aspect of labor, cost, and processing time.